Beta-adrenergic and prostaglandin receptors are being studied in human leukocyte preparations. Examination of the receptor stimulated adenylate cyclases and the biochemical properties of these systems in normal human blood, various psychiatric disorders, and in patients receiving different drugs has been undertaken in order to assess the physiological functioning of the receptors in these states. Experiments directed to the elucidation of the mechanism of coupling between receptor and cyclase have also been started.